It seems that the original Warcraft II is almost becoming a collector's item. It's not available new and it's only sold these days as part of Warcraft II Battlechest. I just ordered Battlechest used for $70. Tides of Darkness alone is selling for $20.

I just checked the Wikipedia page and now I get it: "Warcraft II: Tides of Darkness" is "the original" Warcraft II. The expansion is called Warcraft II: Beyond the Dark Portal. Both original and expansion are sold together as "Warcraft II: Battle Chest".

I'd suggest updating the FAQ page to make this clear. It wasn't at all clear to me what I was supposed to buy to get Wargus to work.